xfs: preallocation transactions do not need to be synchronous

Preallocation and hole punch transactions are currently synchronous
and this is causing performance problems in some cases. The
transactions don't need to be synchronous as we don't need to
guarantee the preallocation is persistent on disk until a
fdatasync, fsync, sync operation occurs. If the file is opened
O_SYNC or O_DATASYNC, only then should the transaction be issued
synchronously.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>

4 files changed, 12 insertions, 2 deletions

diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c
index a55c1b46b219..52aadfbed132 100644
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -896,6 +896,7 @@ xfs_file_fallocate(
         xfs_flock64_t   bf;
         xfs_inode_t     *ip = XFS_I(inode);
         int             cmd = XFS_IOC_RESVSP;
+        int             attr_flags = XFS_ATTR_NOLOCK;
 
         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
                 return -EOPNOTSUPP;
@@ -918,7 +919,10 @@ xfs_file_fallocate(
                         goto out_unlock;
         }
 
-        error = -xfs_change_file_space(ip, cmd, &bf, 0, XFS_ATTR_NOLOCK);
+        if (file->f_flags & O_DSYNC)
+                attr_flags |= XFS_ATTR_SYNC;
+
+        error = -xfs_change_file_space(ip, cmd, &bf, 0, attr_flags);
         if (error)
                 goto out_unlock;
 
diff --git a/fs/xfs/linux-2.6/xfs_ioctl.c b/fs/xfs/linux-2.6/xfs_ioctl.c
index 0ca0e3c024d7..acca2c5ca3fa 100644
--- a/fs/xfs/linux-2.6/xfs_ioctl.c
+++ b/fs/xfs/linux-2.6/xfs_ioctl.c
@@ -624,6 +624,10 @@ xfs_ioc_space(
 
         if (filp->f_flags & (O_NDELAY|O_NONBLOCK))
                 attr_flags |= XFS_ATTR_NONBLOCK;
+
+        if (filp->f_flags & O_DSYNC)
+                attr_flags |= XFS_ATTR_SYNC;
+
         if (ioflags & IO_INVIS)
                 attr_flags |= XFS_ATTR_DMI;
 
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 37d8146ee15b..c48b4217ec47 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -2831,7 +2831,8 @@ xfs_change_file_space(
                 ip->i_d.di_flags &= ~XFS_DIFLAG_PREALLOC;
 
         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
-        xfs_trans_set_sync(tp);
+        if (attr_flags & XFS_ATTR_SYNC)
+                xfs_trans_set_sync(tp);
 
         error = xfs_trans_commit(tp, 0);
 
diff --git a/fs/xfs/xfs_vnodeops.h b/fs/xfs/xfs_vnodeops.h
index f6702927eee4..3bcd23353d6c 100644
--- a/fs/xfs/xfs_vnodeops.h
+++ b/fs/xfs/xfs_vnodeops.h
@@ -18,6 +18,7 @@ int xfs_setattr(struct xfs_inode *ip, struct iattr *vap, int flags);
 #define XFS_ATTR_NONBLOCK       0x02    /* return EAGAIN if operation would block */
 #define XFS_ATTR_NOLOCK         0x04    /* Don't grab any conflicting locks */
 #define XFS_ATTR_NOACL          0x08    /* Don't call xfs_acl_chmod */
+#define XFS_ATTR_SYNC           0x10    /* synchronous operation required */
 
 int xfs_readlink(struct xfs_inode *ip, char *link);
 int xfs_release(struct xfs_inode *ip);